78 lines
2.7 KiB
Python
78 lines
2.7 KiB
Python
import logging
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from typing import Any, Dict, Text, Type, Optional
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from jeeves.core.actions import PROVIDED_ACTIONS
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from jeeves.core.actions.base import Action
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class Singleton(type):
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def __init__(cls, name, bases, attrs, **kwargs):
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super().__init__(name, bases, attrs, **kwargs)
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cls._instance = None
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def __call__(cls, *args, **kwargs):
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if cls._instance is None:
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cls._instance = super().__call__(*args, **kwargs)
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return cls._instance
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class ActionRegistry(metaclass=Singleton):
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actions: Dict[str, str] = {}
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def __init__(self):
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self.logger = logging.getLogger(self.__class__.__name__)
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@classmethod
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def autodiscover(cls):
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"""Loads all provided actions."""
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# TODO: Third party plugins
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registry = cls()
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for action_namespace in PROVIDED_ACTIONS:
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registry.register_action(cls.get_action_cls(action_namespace))
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@classmethod
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def register_action(cls, action_cls):
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registry = cls()
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# namespace = action_cls.id
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namespace = f"{action_cls.__module__}:{action_cls.__name__}"
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if namespace in registry.actions:
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raise cls.ActionNamespaceConflict(
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f"Namespace {namespace} is already registered"
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)
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registry.actions[namespace] = action_cls
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@classmethod
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def get_action_cls(cls, namespace) -> Type[Action]:
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"""Returns the class for the provided action namespace"""
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# Right now actions are being imported and returned dinamically because it's easier,
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# but we will need a way of autodiscover all (or register them manually) and
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# referencing them on a list so the user knows which actions are available.
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modulename, clsname = namespace.split(":")
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try:
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module = __import__(f"{modulename}", fromlist=(clsname,), level=0)
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action_cls = getattr(module, clsname)
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return action_cls
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except ModuleNotFoundError as error:
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raise cls.ActionDoesNotExist(f"Error importing action {namespace}: {error}")
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@classmethod
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def get_action(
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cls, namespace: Text, parameters: Optional[Dict[Any, Any]] = None
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) -> Action:
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"""Returns the instanced action for the provided namespace"""
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action_cls: Type[Action] = cls.get_action_cls(namespace)
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return action_cls(parameters=parameters or {})
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class ActionNamespaceConflict(Exception):
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"""Raised when an action is defined with an already registered namespace"""
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pass
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class ActionDoesNotExist(Exception):
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"""Raised when there's a problem retrieving an action. More info will be available on the message."""
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pass
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